In this chapter, we are going to learn how to deal with problems based on direct and indirect proportions. The NCERT Solutions for Class 8 Maths Direct and Inverse Proportions are prepared and explained by the experts. Chapter 13 direct and inverse proportions contain 2 exercises with 21 questions. The first exercise of this chapter covers questions on Direct proportion and similarly, the second exercise of this chapter covers questions from inverse proportions.
In our daily life, we come across many situations where changes in one quantity results changes in other quantity. In mathematics, two quantities are said to be in proportional - if the values of two quantities are related in such a way that changes in one results in a corresponding change in another quantity. For a better understanding of this chapter, NCERT is providing solved examples, exercises, and daily life activities at the end of every concept. In NCERT Class 8 Maths Chapter 13 Direct and Inverse Proportions we learn about two types of proportion- Direct Proportion and Inverse Proportion and also study there properties with applications. The brief about both proportional are following-
Two values are Directly proportional it means to increase/decrease in one value results in a gradual increase/decrease in other value. Let's take an example:
Example- Sunil goes to the stationery shop to buy two pencils. The two pencils cost him Rs. 4. Next week again Sunil goes to the stationery shop to buy 6 pencils. The six pencils cost in Rs. 12. So, in this situation when the number of pencils increases causes gradual increases in the total cost. It means the number of pencils and total cost are directly proportional.
What is Inverse Proportional?
Two values are Inversely proportional it means decreases in one value results in a gradual increase in other value. Example- If the distance is fixed, speed and time are inversely proportional to each other.
( If Distance is fixed)
|Chapter -1||Rational Numbers|
Q3. Rehman is making a wheel using spokes. He wants to fix equal spokes in such a way that the angles between any pair of consecutive spokes are equal. Help him by completing the following table.
(i) Are the number of spokes and the angles formed between the pairs of consecutive spokes in inverse proportion?
Number of spokes
Angle between a pair of consecutive
Q7. Suppose 2 kg of sugar contains crystals. How many sugar crystals are there in (i) 5 kg of sugar? (ii) 1.2 kg of sugar?
Q1. Observe the following tables and find if x and y are directly proportional.